Disposable face masks have been manufactured for many years. In the medical field, many of these early masks were used in preventing contamination of a patient by the breath of health care personnel. In recent years with increased concern for infection of health care personnel with airborne pathogens, such as the hepatitis B virus, it has become necessary to not only prevent contamination of patients due to exhalation from health care personnel, but also to prevent infection of health care personnel due to inhalation of airborne infection particles. It has become even more important in view of the advent of human immunodeficiency virus (HIV) and the recent increase in infectious tuberculosis associated with many HIV patients.
The rapid increase of infectious diseases, particularly AIDS, has made the use of such protective equipment increasingly important. The Center for Disease Control in Atlanta, Ga., has found that the AIDS virus (HIV) can be passed by contact with body fluids. Contact of AIDS contaminated body fluids with another person's source of body fluids, e.g., eyes, nose, mouth, etc., can pass the disease. Therefore, it is necessary to prevent a patient's body fluids from contacting the face of health care personnel.
Aerosols having airborne liquid and solid particles are generated not only by the exhalation of infected patients, but also by certain procedural manipulations and processes that impart energy to any liquid or microbial suspension. Surgical procedures involving use of drills and saws are particularly prolific producers of aerosols which may contain tuberculosis, HIV or other pathogens from an infected patient. Concern with tuberculosis has been increasing since new strains of the disease show strong resistances to multiple types of drug treatment.
One type of mask is illustrated in U.S. Pat. No. 2,012,505 entitled Mask, issued on Aug. 27, 1935 to S. J. Goldsmith. Another type of disposable face mask is illustrated in U.S. Pat. No. 4,319,567 entitled Disposable Face Mask, issued on Mar. 16, 1982 to M. Magidson. This mask is molded and has been especially configured in an effort to avoid leakage of fluid flow past the edges of the mask. Obviously, leakage cannot be tolerated when attempting to control liquids and/or aerosols. U.S. Pat. No. 4,606,341 entitled Noncollapsible Surgical Face Mask, issued Aug. 19, 1986 to Vance M. Hubbard and Welton K. Brunson shows a conventional rectangular face mask having a trapezoidal pleat. For some operating conditions, rectangularly shaped masks, including the mask shown in U.S. Pat. No. '341, may have less than an optimal fit to prevent the passage of liquids and aerosols between the periphery of the masks and a wearer's face.
Recent developments in surgical face mask have resulted in resistance to liquid penetration from the exterior of such masks. U.S Pat. No. 4,920,960 entitled Body Fluids Barrier Mask, issued on May 1, 1990 to Hubbard, et al., is exemplary of improvements in such masks. U.S. Pat. No. 5,020,533 entitled Face Mask with Liquid and Glare Resistant Visor, issued on Jun. 4, 1991 to Hubbard, et al., is an example of incorporating a visor to protect the face of a wearer from liquids during medical procedures.